Fifth Generation (“5G”) mobile communications depend on millimeter-wave frequencies (e.g., >24 GHz). To realize an antenna gain sufficient to maintain a reliable communication link, for instance with a base station, electronic communication devices will likely need a much higher number of antenna elements positioned in various areas of the electronic communication device for diversity and multiple-input multiple-output (MIMO) applications. One concern with communications at millimeter-wave frequencies is that human tissues, such as skin, bone, muscle, and fat, are very lossy. For example, hand absorption can reduce peak gain of a millimeter-wave antenna array by 12 dB when the hand is around 5 millimeters from the antenna array. Accordingly, power savings can be realized if antenna arrays that are blocked by lossy objects are not used for high-power communications. Additionally, some regulatory entities require that exposure of the human body to radio frequency (“RF”) energy be limited.
Conventionally, various sensors such as capacitive, touch, and infrared (top hat) proximity sensors have been used for hand detection to avoid using antenna elements that are blocked. However, due to the increase in antenna elements needed for communicating at millimeter-wave frequencies, the number of sensors needed for accurate hand detection would be impractical from control, management, power consumption, and cost perspectives.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present teachings. In addition, the description and drawings do not necessarily require the order presented. It will be further appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required.
Apparatus, device and/or method components have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present teachings so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.